Heating of fluids



Feb. 15,1938. I L.-A. MEKLER 3 3 5 HEATING OF FLUIDS Fil ed Dec. 14,1932 zsneets-sheet 1 v lNVENTOR FIG. 2 LEV A. MEKLER -mT EY Feb. 15,1938. A. MEKLER- ,1

HEATING OF FLUIDS Filed Dec. 14, 1952 2 vSheets-Sheet 2 FIG. 3"

INVENTOR LEV A. MEKLER ATT Patented Feb. 15, 1938 Z,ld8,686

PATENT OFFECE HEATING F FLUIDS LevA. Mekler, Chicago, Ill., assignor toUniversal Oil Products Company, Chicago, 111., a corporation of DelawareApplication December 14, 1932, Serial No. 647,167

1 Claim.

This application is a continuation in part of my co-pending application,Serial No. 414,270, filed December 16, 1929 now U. S. Patent No.2,009,092.

This invention particularly refers to a furnace of improved design,specially adapted to heat hydrocarbon oils to the high temperaturesrequired for their conversion and also embodies the methods of heattreatment made possible by the improved form of furnace.

Hydrocarbon oils of different characteristics require different methodsof heating in order to subject them to the conversion conditions mostsuitable for the production of maximum yields of the desired products.It is the purpose of the present invention to provide a furnace ofimproved form wherein better control is obtained over the conditions ofheating to which an oil is subjected and wherein the conditions may bevaried to suit requirements of the particular type of oil undergoingtreatment.

It is the purpose of the present invention to control not only themaximum rate of heating and the maximum temperature to which the oil isheated in the furnace but also to positively and independently controlthe rate at which the oil is heated in various sections of the fluidconduit through which it passes in the furnace. In this manner the typeof heating curve obtained by plotting the temperature attained by theoil at various points throughout the heating coil is positivelycontrolled so that any oil of known characteristics may be subjected tothe type of heat treatment known to be best adapted to produce thedesired results from that particular oil.

It is not within the sphere of the present invention to attempt toclassify the oils of known cracking characteristics with respect to thetype of heating curve most suitable for each oil, nor is it theintention of the present invention to generalize or specify the type ofheating curve most suitable for different classes or groups ofhydrocarbon oils. It is rather the purpose of the present invention toprovide an improved form of furnace wherein each of a wide variety ofoils may be subjected to the previously determined conditions of heattreatment most suitable for the particular oil.

A specific embodiment of the apparatus of the present invention maycomprise a furnace of symmetrical design with respect to the type ofheating employed on opposite sides of a plane through the verticalcenter line of the furnace having a fluid conduit supplied substantiallywith 55 convection heat in the central portion of the furnace and fluidconduits supplied substantially with radiant heat on opposite sides ofthe furnace located along the furnace roof and side walls, a combustionzone with means for independently supplying combustibles thereto beinglocated on each side of the furnace whereby the heating con ditions onopposite sides of the furnace are independently controlled, therebyindependently controlling the rate of heating to which the oil issubjected in the fluid conduit on opposite sides of the furnace.

The accompanying diagrammatic drawings, Figs. 1, 2 and 3 illustrates onespecific form of furnace embodying the features of the present inventionand the methods of operating the fur- 315 nace to fulfill the objects ofthe present invention will be more apparent with reference to thedrawings and the following description thereof.

Fig. 1 is a cross-sectional end-view of the furnace.

Fig. 2 is a sectional plan View of the same structure taken along ahorizontal plane indicated by the line 2--2 in Fig. 1 and Fig. 3 is asectional elevation of the same furnace structure taken through avertical plane indicated by the line 3-3 in Fig. 1.

In the drawings the side walls are designated by the numbers I and I,the end-walls are 2 and 2, the roof 3 and the floor 4. Bridge walls 5and 5 separate combustion and radiant heating zone 6, located, as hereillustrated, on the right hand side of the furnace from a similarcombustion and radiant heating zone 6 located on the opposite side ofthe furnace.

Fluid heating zone I is located between bridge. walls 5 and 5 andcontains a bank 3 of tubes 9 heated substantially by convection heatfrom the furnace gases having passed from combustion zones. 6 and 6'over bridge Walls 5 and 5', respectively, into heating zone 1, thecommingled gases from both combustion zones passing downward around thetubes in bank 8 and out of the furnace through a flue l0, controlled bydamper H to a stack (not shown).

A bank I2 of tubes I3 is. located along the side l and right hand halfof roof 3 and is supplied substantially with radiant heat from thematerials undergoing combustion in combustion zone 6 and from the hotrefractory walls of this zone of the furnace. Another bank i2 of tubesi3 is located along the side wall I' and left hand half of roof 3 andthe tubes of this bank are subjected substantially to radiant heat fromthe flame in combustion zone 6 and the hot refractory surfaces of thiszone of the furnace.

Combustion zone 6 is supplied with combustibles through firing tunnelsl4 located along the side wall I of the furnace, one or any number of aplurality of similar firing tunnels being provided. A plurality offiring tunnels, as shown in the drawings, is preferred in order tosecure uniform distribution of combustibles along the entire length ofthe combustion zone, thereby securing the even distribution of heatalong the length of heating tubes l2. In the case here illustrated,

each firing tunnel consists of a fuel duct I5'to which any desired formof fuel such as oil, gas or pulverized solid fuel is supplied through aburner 2| of any suitable form, together with air or other combustionsupporting material. Ducts I6 and I! located, respectively, above andbelow fuel duct l5 are provided for the purpose of supplying auxiliaryair or steam to the combustion zone. Ducts l6 and I1 contain regulatingdampers l8 and I 9, respectively.

One or a plurality of similar firing tunnels 14 located along side wallI of the furnace supplies combustibles to combustion zone 6'. Firingtunnels I4 are preferably similar to firing tunnels l4 and, in the caseillustrated, the description of the various parts and the appurtenancesto firing tunnels 14 also applies to tunnels l4, primed numbers beingused to designate the parts of firing tunnels l4, corresponding to theparts of firing tunnels [4.

By means of separate combustion zones 5 and 6, separately supplied withcombustibles, as described, firing conditions on opposites sides of thefurnace may be independently controlled, thereby independentlycontrolling the heating conditions around tube banks l2 and [2 wherebythe rate of heating to which the oil is subjected during its passagethrough each tube bank is independently controlled.

The tubes 9, l3 and I3 of banks 8, l2 and I2, respectively, extendbetween the end walls 2 and 2 of the furnace and in the case hereillustrated are connected in series 'by return bends 2!] of any suitableform and in Fig. 1 is illustrated one specific flow through the entireheating coil consisting of tube banks 8, l2 and I2. In the caseillustrated, the oil enters the lower row of tubes in bank 8, passing inseries through adjacent tubes in each row of this bank and out of thetop row of bank 8 into the lower side wall tube of bank l2, passingthrough adjacent tubes of I this bank in series and out of the last rooftube in bank l2 into the adjacent roof tube of bank 12 on the oppositeside of the furnace, passing through the adjacent tubes of bank I2 inseries and finally being discharged out of the furnace from the lowerside wall tube in bank l2.

It will be understood, however, that any desired flow of oil througheach tube bank may be employed within the scope of the invention andthat thelvarious tube banks may be connected in any desired sequence andthat the direction of flow through any tube bank may be the same or thereverse of that shown in Fig. 1. The particular flow through the heatingcoil may be chosen to suit requirements, as may the furnace conditionsemployed in opposite sides of the furnace, and it is not intended toimpose limitations of any specific flow or furnace conditions upon thebroad spirit and scope of the invention.

I claim as my invention:

An oil heating apparatus comprising a furnace having side walls, endwalls, a roof and a floor, a pair of spaced bridge walls dividing thefurnace into two outer compartments and a central compartment, aplurality of horizontally spaced fuel ducts, each provided with aburner, extending through each of said side walls adjacent the floor andadapted to project at least partially burned fuel toward one of saidbridge walls, air ducts contiguous to and positioned above and beloweach of the fuel ducts, means for passing combustion gases from bothsaid outer compartments through the central compartment, heating tubesin each of the outer compartments disposed out of the main path ofcombustion gases there through, and additional heating tubes in thecentral compartment disposed in the path of the combustion gasestherethrough.

LEV A. MEKLER.

